Long term evolution (Long Term Evolution, LTE) time division duplex (Time Division Duplex, TDD) and worldwide interoperability for microwave access (Worldwide Interoperability for Microwave Access, WiMAX) are both TDD technologies, that is, an uplink and a downlink are distinguished on a single frequency time-domain, and frequency bands used by two systems are overlapped at many places. At present, a WiMAX network already has an extensive commercial storage, while the LTE TDD is also facing commercial uses, and becoming an evolution direction of all TDD cellular systems. Currently, some carriers propose requirements of smooth evolution from an existing WiMAX network to an LTE TDD network, and subsequently, more and more WiMAX carriers will gradually implement this kind of evolution. On one hand, these requirements contribute to the emergence of a WiMAX and LTE TDD dual-mode base station, so as to implement a low-cost steady transition from a WiMAX network to an LTE network; on the other hand, these requirements also contribute to the emergence of a networking scenario with coverage WiWAX and LTE together. Air-interface synchronization between an LTE TDD system and a WiMAX system is needed for sharing a radio frequency unit and an antenna in a dual-mode base station, and the air-interface synchronization is also needed for avoiding mutual interferences during networking with coverage of the two systems.